1. Field of the Invention
The present invention relates to electrical connector technology and more particularly, to such an electrical connector, which achieves optimal impedance matching and high structural stability, ensuring high signal transmission quality and reliability.
2. Description of the Related Art
Following fast development of computer technology, high mobility notebook computer has been well developed and widely used by people to substitute for desk computer. Further, when connecting a computer to a peripheral apparatus for transmitting data or signal, a peripheral interface means is necessary. USB (universal serial bus) is the mainstream interface, having hot plug function. However, USB 2.0 is simply applicable to peripheral devices (such as, card reader, printer, memory stick, web-phone, webcam, and etc.) that have the characteristics of low driving power and low transmission speed, not suitable for use in a high storage capacity hard disk drive, DVD programmer or player, or blue-light peripheral device. For high-power and high-speed application, USB 3.0 (USB super-speed) is created. A USB 3.0 connector has a transmission speed as high as 4.8 Gbps, and is compatible with USB 2.0. Further, a USB 3.0 connector supports full duplex and provides up to 900 mA power output. Thus, by means of the application of an USB 3.0 connector, a high storage capacity hard disk drive does not require an extra power cable. The application of USB 3.0 technology allows interruption under standby mode, reducing power loss and providing maximum user flexibility and efficiency.
Further, following the market trend to make computers and peripheral devices having a small size characteristic, the problem of internal signal interference due to magnetic effects must be taken into account. Interferences may come from conducted disturbance that occurs during signal transmission through power circuits and/or signal lines of the circuit board to the electrical connector, or radiated disturbance that occurs due to the radiation of magnetic waves around the electrical connector. As a USB 3.0 connector uses a large number of conducting terminals that are arranged in a limited mounting area, approaching between two conducting terminals or curving of any conducting terminal may cause disturbance (static interference, electromagnetic interference, impedance matching, noise interface, crosstalk interference) during the transmission of a high-frequency signal. Further, EMI (electromagnetic interference) and noises can be eliminated or reduced during signal transmission between a USB 3.0 connector and a system mainboard interface only if impedance matching condition is satisfied. Improper impedance matching can cause signal reflection and noise interference, resulting in signal loss, signal deformation and/or signal distortion. When this problem occurs, the electronic system (computer or network system) may be unable to function normally.
Further, a circuit board design of tongue plate has copper foil contacts arranged on a plane. For example, an HDMI socket connector is based on this design. Further, a circuit board design of tongue plate for USB 3.0 female connector has 5 pcs of copper foil contacts and 4 pcs of springy metal contact terminals. When a USB 3.0 male connector is inserted into a USB 3.0 female connector, the arrangement of the springy metal contact terminals at the circuit board design of tongue plate of the USB 3.0 female connector may causes serious mechanism problems. One first problem is that the positioning of the front contact portions of the springy metal contact terminals on the top side of the circuit board design of tongue plate may be directly impacted by the mating metal contact terminals of the USB 3.0 male connector, due to positioning displacement or large tolerance, causing disconnection of the spring metal contact terminals from the circuit board design of tongue plate. A second problem is that the springy metal contact terminals may be squeezed toward the circuit board design of tongue plate by a lateral force upon insertion of the USB 3.0 male connector into the USB 3.0 female connector, causing damage or disconnection of the rear soldering portions of the springy metal contact terminals from the circuit board design of tongue plate. A third problem is that the circuit board design of tongue plate has no room for allowing the springy metal contact terminals to elastically and heavily deform, and the springy metal contact terminals may be permanently deformed.
Therefore, it is desirable to provide an electrical connector, which eliminates the aforesaid problems.